(a) Field of the Invention
The present invention relates to an etchant and a manufacturing method of a thin film transistor (“TFT”) array panel using the same.
(b) Description of the Related Art
To form metal wiring in a substrate in a display device such as a liquid crystal display (“LCD”), a metal layer is generally formed by sputtering on a substrate, a photoresist is coated and exposed on the metal layer, and the metal layer is etched using the photoresist such that the metal layer is selectively maintained on only a predetermined region to form the metal wiring.
Here, the resistance of the type of metal used in forming the metal layer is an important factor in generating a resistor-capacitor (“RC”) signal delay, and a technique for using metal wiring having low resistance has been developed.
Recently, copper (Cu), which has relatively low resistance and has relatively little negative environmental impact is increasingly gaining attention as a wiring material for low resistance applications, however copper has poor adherence with a glass substrate or a silicon insulating layer such that it is difficult to use as a single layer. To solve this problem, a multilayer including a copper alloy layer, a titanium (Ti) layer, a titanium alloy layer, a molybdenum (Mo) layer, or a molybdenum alloy layer having excellent adherence with a glass substrate or a silicon insulating layer is used as a lower layer below the copper layer.
To etch this multilayer, a peroxide-based etchant is typically used, and if the peroxide-based etchant includes metal ions at more than a predetermined concentration, peroxide decomposition is accelerated and is quickly decomposed into water and oxygen such that heat and a quick composition change may be undesirably generated, thereby generating instability.